Portland, OR Climate & Monthly Averages
Portland has a Mediterranean climate. August is the hottest month, averaging 84° by day; December is the coldest at 46°.
How weather changes through the year in Portland
Portland runs on a dry-summer rhythm: the warmest months are also the driest. July averages 8 mm (0.3 in) while the wet season peaks in December at 8.9 inches (225 mm). Highs range from 46°F (8°C) to 84°F (29°C).
Portland climate quick facts
- Hottest month: August - highs near 84°F (29°C)
- Coldest month: December - highs near 46°F (8°C)
- Decade extremes (2015-2024): 115°F (46°C) high · 6°F (-14°C) low
- Wettest month: December (19 rainy days) · Sunniest: July (13.2 h sun/day)
- Climate type: Mediterranean
- Annual swing: 17°C between the average warmest and coolest month · day to night: 10°C
- Snow: about 9 days a year
- Average humidity: 75%
Temperatures, rain and sunshine
August is the warm end of the year, averaging 84°F (29°C) by day and 59°F (15°C) overnight. December bottoms out at 46°F (8°C) in daylight, 36°F (2°C) after dark. The wettest month is December (8.9 inches (225 mm) across 19 days) and the driest July.
Snow falls on roughly 9 days a year, mostly December through April. 2 months average under 20 mm of rain, the longest unbroken stretch running July through August. Across the gridded 2015-2024 daily record, the highest daily maximum for this location was 115°F (46°C) and the lowest daily minimum 6°F (-14°C).
Where Portland sits among other climates
- Portland sits close to the middle of our dataset on most measures: 53°F (12°C) as an annual average, 53.5 inches (1358 mm) of precipitation and 8.2 hours of sun a day.
These comparisons use the same ten-year window for every city in the dataset.
Monthly climate table
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 47° | 36° | 19 | 7.5 in | 4.1 h/day | 9.1 h | 61% | 85% |
| February | 48° | 35° | 16 | 5.9 in | 5.2 h/day | 10.3 h | 58% | 83% |
| March | 54° | 38° | 17 | 5.4 in | 7.4 h/day | 11.8 h | 55% | 80% |
| April | 59° | 42° | 15 | 4.4 in | 8.9 h/day | 13.5 h | 51% | 76% |
| May | 67° | 48° | 11 | 2.8 in | 10.1 h/day | 14.9 h | 35% | 73% |
| June | 75° | 53° | 8 | 2.2 in | 12.0 h/day | 15.7 h | 26% | 66% |
| July | 83° | 58° | 2 | 0.3 in | 13.2 h/day | 15.3 h | 7% | 58% |
| August | 84° | 59° | 3 | 0.5 in | 12.1 h/day | 14.1 h | 9% | 59% |
| September | 75° | 54° | 8 | 2.5 in | 9.9 h/day | 12.5 h | 26% | 68% |
| October | 63° | 47° | 12 | 5.4 in | 7.1 h/day | 10.8 h | 40% | 79% |
| November | 52° | 40° | 17 | 7.5 in | 5.1 h/day | 9.4 h | 57% | 84% |
| December | 46° | 36° | 19 | 8.9 in | 3.8 h/day | 8.7 h | 63% | 86% |
Portland month by month
Each card shows the average high and low. The bar places that month between Portland's coldest night and warmest afternoon.
January
- Rain
- 19 days
- Sunshine
- 4.1 h
- Daylight
- 9.1 h
- Snow
- 1 day
February
- Rain
- 16 days
- Sunshine
- 5.2 h
- Daylight
- 10.3 h
- Snow
- 2 days
March
- Rain
- 17 days
- Sunshine
- 7.4 h
- Daylight
- 11.8 h
- Snow
- 2 days
April
- Rain
- 15 days
- Sunshine
- 8.9 h
- Daylight
- 13.5 h
- Snow
- 1 day
May
- Rain
- 11 days
- Sunshine
- 10.1 h
- Daylight
- 14.9 h
June
- Rain
- 8 days
- Sunshine
- 12.0 h
- Daylight
- 15.7 h
July
- Rain
- 2 days
- Sunshine
- 13.2 h
- Daylight
- 15.3 h
August
- Rain
- 3 days
- Sunshine
- 12.1 h
- Daylight
- 14.1 h
September
- Rain
- 8 days
- Sunshine
- 9.9 h
- Daylight
- 12.5 h
October
- Rain
- 12 days
- Sunshine
- 7.1 h
- Daylight
- 10.8 h
November
- Rain
- 17 days
- Sunshine
- 5.1 h
- Daylight
- 9.4 h
December
- Rain
- 19 days
- Sunshine
- 3.8 h
- Daylight
- 8.7 h
- Snow
- 2 days
Looking for warmer alternatives? Browse warm places by month, or compare Portland's coolest part of the year: December, January, February.
A season-by-season guide to Portland
Spring (March through May)
Spring in Portland is crisp but comfortable, with daytime highs averaging 60°F (16°C) and nights around 43°F (6°C); rain falls on around 43 of the 90 days, plus about 3 snowy days.
Summer (June through August)
Summer in Portland sits firmly in the heat, with daytime highs averaging 81°F (27°C) and nights around 57°F (14°C); rain comes on about 13 days over the three months. Daylight is generous - around 12.4 hours of sun a day.
Fall (September through November)
Fall in Portland is crisp but comfortable, with daytime highs averaging 63°F (17°C) and nights around 47°F (8°C); rain falls on around 37 of the 90 days.
Winter (December through February)
Through winter, Portland is brisk and cold: 47°F (8°C) by day, 36°F (2°C) after dark, and rain falls on around 55 of the 90 days, plus about 6 snowy days.
Questions people ask about Portland's climate
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The most useful weather window for Portland
Best time to visit Portland
May to July and September is the sweet spot for Portland - the dry season is running but the afternoons are still bearable. Expect 75°F (24°C) in the afternoon and around 7 days of rain in a typical month of it. For the same question asked the other way round, see where else is warm in May.
What to pack
Pack for Portland with light clothing for the warm months, a warm jacket and layers for the cooler season, proper waterproofs rather than an umbrella - wet days are the norm here and moisture-wicking fabrics for the humidity. Note the gap between afternoon and night: August pairs 84°F (29°C) with 59°F (15°C).
Portland temperature extremes in the 2015–2024 dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.